Initial performance of the CUORE-0 experiment

CUORE-0 is a cryogenic detector that uses an array of tellurium dioxide bolometers to search for neutrinoless double-beta decay of $$\mathrm {^{130}Te}$$. We present the first data analysis with $$7.1 \,\mathrm {kg\cdot y}$$ of total $$\mathrm {TeO_2}$$ exposure focusing on background measurements and energy resolution. The background rates in the neutrinoless double-beta decay region of interest (2.47 to $$2.57 \,\mathrm {MeV}$$) and in the $$\alpha $$ background-dominated region (2.70 to $$3.90\,\mathrm {MeV}$$) have been measured to be $${0.071\pm 0.011}$$ and $${0.019\pm 0.002}\,\mathrm {counts/(keV\cdot kg\cdot y)}$$, respectively. The latter result represents a factor of 6 improvement from a predecessor experiment, Cuoricino. The results verify our understanding of the background sources in CUORE-0, which is the basis of extrapolations to the full CUORE detector. The obtained energy resolution (full width at half maximum) in the region of interest is $$5.7\,\mathrm {keV}$$. Based on the measured background rate and energy resolution in the region of interest, CUORE-0 half-life sensitivity is expected to surpass the observed lower bound of Cuoricino with one year of live time